Methods of producing monocyclic aromatic hydrocarbons such as BTX (benzene, toluene and xylene) from an oil feedstock such as a cracked light oil (hereinafter light cycle oil and also abbreviated as “LCO”) containing a large amount of polycyclic aromatics obtained from a fluid catalytic cracking (hereinafter also abbreviated as “FCC”) unit, or a light naphtha, heavy naphtha or the like obtained from a crude oil distillation unit, using a catalytic aromatic production reaction that employs an aromatic production catalyst are already well known.
The production systems of aromatic hydrocarbons using aromatic production catalyst generally employ a fixed bed system, a moving bed system or a fluidized-bed system. In Patent Document 1, a producing method of monocyclic aromatic hydrocarbons employing a fluidized-bed system is disclosed. In a cracking and reforming apparatus employing fluidized-bed system, the aromatic production catalyst and the feedstock can maintain in a state of similar to a complete mixing, and the reaction temperature becomes easy to maintain uniformly. In addition, the aromatic production catalyst, which is deteriorated by coke in a case where the feedstock becomes heavier, is withdrawn appropriately from the cracking and reforming reactor, and an adhered coke is burned, and thereby heating the aromatic production catalyst can be performed smoothly.